Headless set screw



Patented Apr. 1, 1930 MARTIN L. MAn'rUsor woonnnnr, conNEo'rIcUr HEADLEss sE'r sonnw IApplication tlled February 24,1927. Serial No. 170,519.

' 'llhis invention relates to certain new and useful improvements in headless set screws such as are designed to be embedded in the member in which they are seated, for the pure pose of securing the same to a shaft or other i member, as `for example in the attachment of a collar or pulley ona shaft, or the like, and

in a way to lock the parts Atogether and securely hold thesame, with a View of prevent- 1l)l Ving the turning of the collar or pulley upon the shaft.

The object of the invention is to provide a i,

hollow form of set screw including an annular thread upon its peripheral surface and a slot l5 1n its side topermit ofslight expansion and contraction, and particularly .to provide a tapered annular lower end portion and an inner annular tapered top end portion, the two said tapered portions being of substantially the same size and proportion, so that the tapered lower end portion of one screw .may be seated in the tapered inner annularA end portion of a similar screw for the purpose of spreading andlocking the same after it has beenseated as in use'.

A further feature of the invention is to provide internal-longitudinal recesses in the inner side wall of the screw having shouldered portions that are in alignment with the longitudinal center or axis of the screw, and against which the corresponding shouldered portions of ribs upon a wrench'may be seated, and whereby the said screws are turned into and out of suitably tapped screw holes.

With these and other objects in view, the invention resides and consists in the construction and novel combination and arrangement of parts hereinafter more fully described,

40 illustrated in', the accompanying drawings,

and pointed out in the claims hereto yappended, it being understood that various changes in the form, proportion, size, and minor details of construction within the scope of the claims may be resorted to withoutldeparting from the spirit, or sacrificing any of the advantages of the invention.

Similar characters of reference denote llike or corresponding parts throughout the sev,-

Y'eial'gures of the accompanying drawings responding with the showing'ef the inner forming a part of this specification and upon which! l Fig. 1 shows an .enlarged sectional elevational view, of two set screws constructed in accordance with my invention and positioned one against the other in a threaded hole of a l collar or other member mounted upon a shaft;

F ig. 2 is a vertical longitudinal sectional view of one of my improved screws, and corscrew of Fig. 1; f*

.F ig. 3 is a plan view of the screws shown inFigs.1and2; f

Fig. 4 is a'. side elevation of the screws lshown in the preceding figures, said View bein taken from the right of the screw shown in igs.1vand2;

Figs. 5 and 6 show top pla-n views of screws .of the same general character and illustrating different forms and umbers of recesses for the shouldered ribs o` the wrench, as well as the expansion slot as in the other ligures;

Fig'. 7 shows a further plan View of a screw having a slot for expansionand pockets for the attachment of a wrench and whereby with 5 the turning of the screw with a wrench, a more binding effect of the screw in its pocket is obtained; and Fig. S shows a small side view of a wrench adapted for turning the screws inthe thread- 'S9 ed holes. Referring in detail to the characters of reference marked upon the drawings, the set screw as will be seen is a headless form of peripherally threaded screw made of a single S5 `'piece of metal having a solid lower end portion 10 and a hollow upper body portion forminga socket 11. A longitudinal slot 12 is provided in one side ofthe body, preferably of the depth of the socket 11, which permits the annular body portion to be expanded. The lower end of the screw is provided with a beveled annular peripheral portion 13 for engagement with la shaft or member '14, o against which the screw is to be seated. The v upper annular end portion of the body of the screw is provided with an inner lannular beveled seat 15 ofsubstantially the same size and taper as thelower annular beveled. portion ofthe screw so that when saidscrews are holein which it is seated so as to preventv positioned one against the other, the outer screw may be tightly set into the beveled end socket of the irst mentioned screw, in a way to spread the same and lock it in position against further turning. The said action obviously serves to spread the upper cylindrical end peripherally threaded portion of the inner screw, against the threaded wall of the tapped movement 'of the screw after it has once been set in position. ,f A The screws may be turned and set by any suitable means, preferably a simple form of v wrench somewhat like that illustrated in Fig.

8, and having a round elongated end portion 16 of a size and shape to fit into the socket of the body portion 11, of the screw and further includes a longitudinal ribor projection 17 to enter thebefore mentioned slots 12 in a way to insure the turning ofthe screw with the said. wrench.

These screws may also be provided with vertical grooves 18 in theside wall of the -socket 11, of the body, as seenin Figs. 5,6 and 7. The sides of these grooves, speciically designated as 19, are preferably formed in radial alignment with the center or axis ofthe screw in a way to form a better engagement of the ribs on the wrench with the body of the screw as will be apparent.

For a screw of the type shown in Figs. 5, 6

and' 7, having longitudinal pockets formed made, hence the screw can-beset up tighter with less eort.

Having thus described my invention, what is provided With'a wrench engaging shoulder.

v Signed at Waterbury in the lcounty of New Haven and State of Connecticut, this 21st-day of February, A. D. 1927.

e MARTIN L` MARTUS.

l claim and desire to secure by Letters Patentvv 1s:, e 1. A` headless expandible set screw of the character described including a solid lower end portion having a portion of its peripheral surface tapered and the remainder thereof threaded, a socket in its upper end portion, a longitudinal slot'in the side of the screw opening and extending only to the depth of the socket, and an inner annula'rtapered top endportion surroundin the open end of. the.

socket and adapted to expanded into locking engagement with its seat' by the correspondingly tapered end portion of a similar screw when positioned thereagainSt, either oneof said screws being capbleoi use as a'set screw or as a locking membenf'- 2. The structure as set forth in claim 1` in which the socket below its. tapered portion 

